Mark Cuban ( and Todd Wagner sold their company,, to Yahoo for $5.7 billion in 1999. Months later, Cuban bought the Dallas Mavericks.

Founder, president, and CEO
New York, New York

Can you lose what you never had? It felt that way to me.

It was December 1999. I'd sold my dot-com for $42 million. My two partners and I each walked away with $8 million in stock. I'd grown up poor, the son of Greek immigrants. This was a dream come true.

Then the dream ended. From the day of the sale until the day when I could legally sell my shares, the stock tanked. I ended up with a fraction of my original take. Then Bill Gross at Idealab courted me as an entrepreneur-in-residence. Idea-lab was about to go public. Theoretically, my options could have been worth $40 million. Then the Internet market collapsed; Idealab never went public, and my options were worthless.

I lost everything - twice. But worse than losing the wealth was losing my identity. I couldn't even think about working again. Today, I have a certain sense of calm. Those years were the most amazing period of my life. But they warped my priorities. There was a time when I was so obsessed with my company that my girlfriend left me. It was only after I had lost my fortune that she took me back.